#include<stdio.h>
int main(){
	int iMonth=0,iDay=0;
	printf("enter the month you want to konow the days\n");
	scanf("%d",&iMonth);
	switch(iMonth){
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12:
			iDay=31;
			break;
		case 4:
		case 6:
		case 9:
		case 11:
			iDay=30;
			break;
		case 2:
			iDay=28;
			break;
		default:
			iDay=-1;
			break;
	}
	if(iDay==-1){
		printf("there is a error with you enter\n");
	}else{
		printf("2017,%d has %d days\n",iMonth,iDay);
	}
	return 0;
}
